102 



TWENTY-EIGHTH FRUIT-GROWERS' CONVENTION. 



lice, and which lays us under a vast debt of gratitude for its destruction 

 of aphids, is also a foe to the pestiferous thrips. A predaceous bug, not 

 very distant in relationship from the bedbug (Triphleps insidiosis) , is 

 often seen with a thrips on its beak or rostrum. It also banquets on 

 aphids and young scale insects. Without doubt sporozoa and fungi 

 prey upon thrips. Thaxter has taken a species of Empusa from larval, 

 pupal, and adult thrips which it had destroyed. Pettit thinks he has 

 taken a sporozoan from thrips in Michigan. But without doubt rain 

 is the most formidable enemy of the thrips. I feel certain that a heavy, 

 dashing rain will kill them by the millions. Possibly our misfortune 

 of the past two months is to be coordinated with our gentle rains and 

 absence of severe downpours. 



Remedies. — Without doubt the distillate spray, which I believe is to be 

 • the greatest boon in the way of insecticides yet discovered, will be 

 quick death to the thrips. Thus it will give a triple benefit: kill the 

 scale, with many of their eggs, and destroy them in more mature growth 

 than will fumigation; kill the red mite (red spider), and many, if not 

 most of their eggs; and last will kill these baneful thrips. I have yet 

 to hear of any spotting of oranges in orchards that were sprayed within 

 a few weeks of the time — February — when the spotting occurred. 



PARASITES OF INJURIOUS INSECTS. 



By DR. W. B. WALL, of Santa Ana. 



Possibly many of us have not given sufficient thought to the wonder- 

 ful work and incalculable value of the parasites of injurious insects, 

 many of them so small that they can scarcely be seen by the unaided 

 eye, and yet they have done a work impossible to man. Without them, 

 in a very few years, injurious insects would consume or destroy nearly all 

 vegetation; so our very existence is largely dependent upon them. After 

 their beneficial mission has been accomplished, they in turn would 

 become an intolerable nuisance but for their self-limitation by the con- 

 suming of their own food supply. In this way nature keeps up an equi- 

 librium, except where man interferes with her plan, by transplanting to 

 a new field, injurious insects to pursue their work of ruin, unrestrained 

 by their natural parasites. 



It is needless to say that California is preeminently kind to all life, 

 animal and vegetable, and that man has been drawn here from every 

 quarter of the world. Either carelessly or ignorantly, he has brought 

 with him, or afterward imported, many, if not all, the injurious insect 

 pests with which we are afflicted. It matters not how they get here; 

 when here, they live, multiply and destroy. 



